Thanks to Dave A. for the tip: Amazon is selling a 13-month Xbox 360 Live Subscription Gold Card for just $29.95, a savings of $20:

Product Features

Subscription Term Name: 12+1 Months

  • Buy 12 months and receive an extra month free
  • Sign up with or without a credit card
  • Gold lets you experience all Live content the day that it is put up
  • Use Live Gold to play all of your multiplayer enabled games online
  • Voice and video chat enabled

That's a smoking deal. Even if your subscription isn't going to expire soon, it's worth snagging now.